Backfire release



A ril 3, 1934. P. H. MAURER 1,953,086

BACKFIRE RELEASE Filed June 18, 1932 [N'VENTOR @auZf/f M101" Patented Apr. 3, 1934-- issaoso *PATEN OFFICE BACKFIRE RELEASE Paul H. Maurer, Clifton, it} 3., assignor to Eclipse Elmira,

Machine Company New York N: 5., a corporation Application June l8, l932 Serial Non 618,949

automatic starting mechanism and more partied-=- larly to means for preventing automatic" actua tion of a starting mechanism during backward rotation of the engine.

In automatic starting mechanisms which include gear drives adapted to engage automatically upon actuation of the starting mechanism is desirable to avoid such engagement dining hawkward rotation of the engine in order to avoid unnecessary and undesirable stresses on the engaging parts and associated elements.

Backward rotation oi the engine may occur merely as a back rock -prior to coming to rest after forward rotation or may be a persistent backward rotation.

' It is an object oi the present invention to pro vide a novel device of this character which is reliable and eflicient in operation and simple and economical in construction.

It is another objectto provide such a device which is effective to the starting mech= anism inoperative until manually released by the operator. l It is another object to provide such a devlc which is arranged so as not to interrupt the cranking operation by reason of back pressures in the intake system due to backfire or otherwise while the engine is being cranked It is ,a further object to provide such a detdce which is adapted to be used in conjunction with a time delay mechanism for the automatic start ing me. 7

It is another object of the present invention to provide such a device in which the backfire release and the time delay are arranged to supplement each other whereby the backfire release will not function during the operation of the two delay.

Further objects and advantages will be apparentto those skilled in this art from the following description taken in connection with the acco panying drawing in which:

Thisinvention relates to a backfire release for NIL 229M81 Fig. l is a semi-diagrammatic representation of a preferred embodiment of the invention;

Fig. 2 is a detail showing a modified form oi the control device for the backfire release.

Referring first to l of the drawing, t ere is illustrated a starting system for an interned. combustion engine, not illustrated, including c3 battery l, grounded at 2 and connected by a lead 3 to a magnetic starting switchindicated gencr= ally at The starting switch is connected through a single tum coil 5 and lead c to a start= ing motor SM which is grounded at "l to com=- plete the starting circuit. l

A. solenoid i3 is arranged to operate the switch by means of a control circuit including a manual switch and two sets of automatically con trolled contacts arranged'in series whereby openof any one or" the three circuit controlling devices prevents ehective energization oi solenoid ll. As here shown the control circuit includes manual switch 9 connected to the battery lead 3, lead ll, lead X 12, spring strip 13,- contact 1c mounted thereon, fixed contact 15, lead 16, hired contact 1'2", and contact '18 mountedion spring strip is which is grounded at 21 to complete the" control circuit. Contacts it; 15 and 17, 1% are normally closed whereby initial closure oi? the -manual switch 9 completes the control circuit;

Means are provided for opening contacts it; 18 when the engine starts and for maintaining said contacts open during self-operation of the engine including a lever 22 adapted to engage weight member 23 on the end of the spring ship is and tend the strip backward, and a magnetic plunger 24 connected to operate said lever.. The plunger 24 is normally maintained in its upper position by yielding means such as a spring so hut is arranged to he attracted downwardly by a solenoid 26 which is connected at one end by a lead 2'? to the starting motor side of the starting switch d and is grounded at its opposite end at so, A generator coil 29 is arranged to the plunger 2c in its lower position during selloperation of the engine. Coil 29 is connected by a lead Bl to an engine driven generator G and 3 is also grounded at 28.

Weight member 23 is so formed that release thereof when the plunger is returned to idle position by the spring 25 causes a pendulous vl- I tive to close the starting switch 4. As here shown this is accomplished by opening contacts 14, 15

and maintaining said contacts open so long as the manual switch 9 remains closed. For this purpose a non-magnetic plunger 32 is provided having an insulated tip 33 to engage the spring strip 13 and move contact 14 out of engagement with contact 15. The plunger .32 is arranged to be actuated 'by pressure responsive means, here shownas a flexible diaphragm 34 mounted in a chamber 35 having a nipple 36 adapted to be connected to a suitable part of the fuel intake system of the engine such as the intake manifold 30." As illustrated, the diaphragm 34 is formed to normally assume a depressed condition, but is adapted to be moved by pressure in the chamber 35 to raise the plunger 32 and open contacts 14, 15. It will be understood that any suitable form of pressure responsive means such, for instance, as a slidable piston may be used to actuate the plunger 32.

In order to maintain these contacts open as long as the manual switch 9 is closed, a magnetic armature 37 is suitably fixed on the plunger 32, and a solenoid 38 is arranged to surround the plunger 32 above said armature 37 and is connected by leads-39 'and 41 in shunt with said contacts. It will thus beseen that the solenoid 38 is normally deenergized even when the control circuit is closed since it is shorted by the contacts 14, 15 but when these contacts are opened, the current flowing through the control circuit is compelled to traverse said solenoid, thus causing the-armature 3'7 to be attracted to maintain said contacts open until the control circuit is broken. v I I Solenoid'38 is so wound that its resistance is sufficient to prevent energization of solenoid 8 ,to the degree necessary to efiect closure of the starting switch. However, it is arranged not to prevent suflicient energization of solenoid 8 to retain the starting switch closed, such retention requiring much less magneto-motive force than the initial closure thereof by reason of the closure of the magnetic circuit of solenoid 8. It will thus be seenthat the cranking operation will not be interrupted by opening of contacts 14, 15 due to backfire or other causes during such cranking.

In operation, and starting with the parts in the positions illustrated, closure of the manual switch 9 9 completes the control circuit energizing solenoid 8 and causing closure of the starting switch 4 whereby the starting motor is energized to crank 'the engine. At this time the solenoid 26 is energized, but is prevented from retracting the magnetic plunger 24 to its lower position by reason of the heavyflow of cranking current through the single turn coil 5 which acts in opposition thereto. When the engine starts, the reduction in the current through the single turn coil 5 allows the solenoid 26 to move plunger 24 to its lower position, causing lever 22 to bend back the spring strip 19 and open contacts 17, 18.

7 a to rest. During this period of vibration, the solenoid 8 is prevented by its self-inductance from being efiectively energized. When contact 18 the pressure in chamber 35 persists after-the expiration of the time delay, when the contact 18 comes to rest against contact 17 solenoid 38 will be energized, retainingthe plunger 32 in its upper position as long as the manual switch 9 remains closed. The starting mechanism is thus maintained inoperative regardless of the further duration of the backfiring conditions. When backfiring ceases, all that is necessary is for the operator to open the manual switch 9 whereupon solenoid 38 is deenergized, allowing the contacts 14, 15 to close. Upon reclosure of the manual switch therefore the automatic starting operation will take place in the usual manner.

It will be noted that by reason of the arrangement of the time delay contacts 17, 18 in series with the backfire release solenoid 38, a back rock of the engine or a backfire which does not persist longer than the time delay period will not cause energization of the solenoid 38, so that plunger 32 will be allowed to return to its normal position as soon as the pressure in the chamber 35 is relieved, thus reclosing contacts 14, 15 without the necessity of the operator actuating the manual switch 9. In other words, the backfire release is arranged to be supplemental to the time delay and does not operate to prevent actuation of the starting mechanism except when such operation is made necessary by a condition which the time delay alone will not control.

In Fig. 2 there is illustrated a slightly diiTerent arrangement of the backfire release mechanism in which the solenoid 38 is provided with a fixed magnetic core 42 and the spring strip 13 carrying contact 14 is provided with a magnetic armature 43 in proximity to the end of the core 42. The spring strip 13 is arranged to be initially actuated by a non-magnetic plunger 44 slidably mounted in a cap 45 of the chamber 35 and actuated by the diaphragm 34 within said chamber in the manner previously described. The remaining elements of this embodiment of the inventionare similar to those illustrated in Fig. 1. and the operation thereof is the same as above set forth. I

Although certain structural embodiments of the invention have been illustrated and described in detail, it will be understood that the embodiments shown are not exclusive and that various changes may be made in the construction and arrangements of the parts without departing from the spirit of the inventionas defined in the claims appended hereto.

What is claimed is:

1. In combination with an internal combuse .tion engine, a starting system therefor including tion engine, a starting system therefor including i a magnetic starting switch, a control circuit for said magnetic switch, means responsive to backward rotation of the engine for inserting a resistance in the control circuit sumcient to prevent actuation of the starting switch thereby, and means under the control of the operator for retaining said resistance in said circuit.

3. In combination with an internal combustion engine, a starting system therefor including a magnetic starting switch, a control circuit for said magnetic switch, means responsive to backward rotation of the engine for inserting a resistance in the control circuit sufficient to prevent ctuation of the starting switch thereby, means under the control of the operator for retaining said resistance in said circuit, and means for delaying the action of the retaining means for a predetermined time.

4. In combination with an internal combustion engine, a starting system therefor including a magnetic starting switch, a control circuit for said magnetic switch, means responsive to self operation of the engine for opening said control circuit, means for delaying reclosure of the control circuit for a predetermined time after forward rotation of the engine ceases, means responsive to backward rotation of the engine for rendering said control circuit inoperative, and means under the control of the operator for maintaining said control circuit inoperative.

5. In combination with an internal combustion engine, a starting system therefor including a magnetic starting switch, a control circuit for said magnetic switch including a pair of normally closed contacts, means including a magnetic coil in shunt therewith for controlling said contacts, and means responsive to backward rotation of the engine for opening said contacts.

6. In combination with an internal combustion engine, a starting system therefor including a magnetic starting switch, a control circuit for said magnetic switch including a pair of normally closed contacts, means including a magnetic coil in shunt therewith for controlling said contacts, and means responsive to backward rotation of the engine for opening said contacts, and means for maintaining said control circuit open during self-operation of the engine and for delaying reclosure thereof until a predetermined time after forward rotation of the engine has stopped.

7. In combination with an internal combustion engine having a fuel intake system, a starting system therefor including a magnetic starting switch,-a control circuit for said magnetic switch including a pair of normally closed contacts, means including a magnetic coil in shunt therewith for holding said contacts open, means responsive to pressure in the intake system for opening said contacts, and means for preventing energization of the magnetic coil for a predetermined time after forward rotation of the engine has stopped.

8. In combination with an internal combustion engine, a starting system therefor including a magnetic starting switch, a control circuit for said magnetic switch including a pair of normal- 1y closed contacts, means including a magnetic coil in shunt therewith for. controlling said contacts, means responsive to backward rotation of the engine for opening said contacts, and a manually operable switch for opening said control circuit.

9. In combination with an internal combustion engine, a starting system therefor including a magnetic starting. switch, a control circuit for said magnetic switch including two sets of contactsin series, means responsive to self-operation of the engine for opening one set of contacts, means responsive to backward rotation of'the engine for opening the second set of contacts, and electro-magnetic means controlled by the first set of contacts for holding open the second set of contacts.

10. In combination with an internal combustion engine, a starting system therefor including a magnetic starting switch, a control circuit for said magnetic switch including two sets of contacts in series, means responsive to self-operation of the engine for opening one set of contacts, means for delaying reclosure thereof until a predetermined time after self-operation of the engine ceases, means responsive to backward rotation of the engine for opening the second set of contacts and electromagnetic means controlled by the first set of contacts for holding open the second set of contacts.

11. In combination with an internal combustion engine, a starting system therefor including a magnetic starting switch, a control circuit for said magneticswitch including two sets of contacts in series, means responsive to self-operation of the engine for opening one set of contacts, means responsive to backward rotation of the engine for opening the second set of contacts, electro-magnetic means controlled by the first set of contacts for holding open the second set of contacts, and manual means for deenergizing said holding means.

12. In combination with an internal combustion engine, a starting system therefor including a magnetic starting switch, a control circuit for said magnetic switch, a resistance element, and means responsive to backward rotation of the engine for inserting said resistance in the control circuit, said resistance being suflicient to prevent closure of the starting switch, but allowing retention of the starting switch in closed position. i

13. In combination with aninternal combustion engine having a fuel intake system, a starting system therefor including a magnetic starting switch, a control circuit for said magnetic switch, a resistance element in said control circuit suflicient to prevent closure of the starting switch, but allowing retention of the starting switch in closed position, means normally shorting said resistance, and means responsive to pressure in the intake system of the engine for opening said shorting means.

PAUL H.- MAURER. 

